Electric connector and method of forming a connection

ABSTRACT

An electric elbow connector includes a generally L-shaped hollow enclosing structure having a generally L-shaped conducting structure mounted therein and formed of three pieces including a contact body having formed therein a pair of angularly related contact making passages in one of which the shank end of a contact sleeve is disposed and in the other of which a contact pin is threadedly mounted in such manner that the end thereof is disposed in high pressure contact with the side of the shank of the contact sleeve. The pressure applied to the shank of the contact sleeve by the contact pin is insufficient to exceed the elastic limit of the contact body but is sufficiently great to impart deformation thereto whereby a springlike action is achieved resulting in substantially constant contact pressure between the contact body and the shank of the contact sleeve and between the contact pin and the contact body as well as between the contact pin and the side of the shank of the contact sleeve. An electric conductor is interconnected with the contact sleeve in known manner and the contact pin engages the terminal of an electric device such as a power transformer or the like.

United States Patent [1 1 Zemels 1 ELECTRIC CONNECTOR AND METHOD OF FORMING A CONNECTION [75] Inventor:

[52] US. Cl. 339/59 R, 339/108 R, 339/111, 339/272 R [51] Int. Cl H0lr 7/12 [58] Field of Search 339/111, 143, 61 R, 339/272 R, 60 R, 94 R [56] References Cited UNITED STATES PATENTS 3,711,808 l/1973 Swehla 339/60 C 3,509,516 4/1970 Phillips 339/111 X 2,297,785 9/1942 Lake 339/276 T X 1,678,082 7/1928 Rottenburg. 339/217 N X 2,840,676 6/1958 King 339/60 R X 1,927,267 9/1933 James 339/272 R X 3,376,541 4/1968 Link 339/61 R 3,617,987 11/1971 Sankey 339/111 Primary Examiner-Marvin A. Champion Assistant Examiner--William F. Pate, lll Att0rney-Walter M. Rodgers NJ-m [ 1 Oct. 23, I973 [57] ABSTRACT An electric elbow connector includes a generally L- shaped hollow enclosing structure having a generally L-shaped conducting structure mounted therein and formed of three pieces including a contact body having formed therein a pair of angularly related contact making passages in one of which the shank end of a contact sleeve is disposed and in the other of which a contact pin is threadedly mounted in such manner that the end thereof is disposed in high pressure contact with the side of the shank of the contact sleeve. The pressure applied to the shank of the contact sleeve by the contact pin is insufficient to exceed the elastic limit of the contact body but is sufficiently great to impart deformation thereto whereby a springlike action is achieved resulting in substantially constant contact pressure between the contact body and the shank of the contact sleeve and between the contact pin and the contact body as well as between the contact pin and the side of the shank of the contact sleeve. An electric conductor is interconnected with the contact sleeve in known manner and the contact pin engages the terminal of an electric device such as a power transformer or the like.

4 Claims, 7 Drawing Figures PATENTEB IIBT 23 I973 ELECTRIC CONNECTOR AND METHOD OF FORMING A CONNECTION Known connectors include a hollow L-shaped housing in which two elongated conducting elements are mounted to form an L-shaped current carrying structure. These conducting elements comprise a contact sleeve provided with a transverse threaded passage at one end and a contact pin one end of which is threaded into the transverse passage of the contact sleeve. In order to increase contact pressure, a .slit is formed in the contact sleeve in a direction parallel to the axis thereof and a pair of washer elements are mounted therein and disposed about the threaded end of the contact pin. These washers tend to impart pressure in an axial direction to the interrelated threads of the contact sleeve and the contact pin on the one hand and to the adjacent shoulder of the contact pin and the side of the contact sleeve on the other hand. In this arrangement, the contact pin shoulder frictionally engages an exterior surface of the contact sleeve and due to the substantial radius thereof from the center of rotation of the contact pin, significant frictional moment impedes the tightening of the contact pin. Since the contact sleeve is provided with a transverse threaded opening, it is necessary properly to orient the contact sleeve in a rotary and in an angular sense relative to the incoming conductor so that threaded engagement of the end of the contact pin with the transverse passage in the contact sleeve may be effected. Thus this known arrangement requires installation procedures which are tedious, time consuming and costly.

According to this invention, installation procedure is greatly facilitated and orientation problems are eliminated by constructing a connector of three pieces wherein the shank end of a contact sleeve is interconnected with a contact pin through a contact body in which a pair of angularly related contact making passages are formed. These passages intersect each other and one is threaded to receive the threaded end of the contact pin in such manner as to engage the side of the shank end of the contact sleeve. According to a feature of the invention, the contact body is constructed of conducting material and the force applied to the shank of the contact sleeve by tightening the contact pin is such as to impart a degree of deformatinon to the contact body but is insufficient to exceed the elastic limit thereof. By this means, the contact body in effect constitutes a spring whereby substantially constant contact pressure is established between the shank of the contact sleeve and the end of the contact pin and between the contact body and each of these elements. Thus changes in temperature of the current carrying elements due to changes in ambient conditions or due to changes in electric conditions do not impede the current carrying capacity of the connector. Furthermore since the contact sleeve is inserted into an unthreaded opening formed in the contact body, proper orientation axially and rotationally of the contact sleeve relative to the contact body is automatically achieved for any orientation of the contact sleeve and its associated conductor.

For a better understanding of the invention reference may be had to the following detailed description taken in conjunction with the accompanying drawings in which FIG. 1 is an overall perspective view of an elbow connector formed according to the invention;

FIG. 2 is a view similar to FIG. 1 but which is shown in section so as to depict the assembled relationship of the internal parts;

FIG. 3 is an exploded perspective view of the conducting elements formed according to this invention;

FIG. 4 is a view somewhat similar to FIG. 2 and which depicts a special tool used to perform one step in the assembly of the connector;

FIG. 5 is a view somewhat similar to FIG. 3 and which illustrates the use of another auxiliary tool used in assembling the connector;

FIG. 6 is an enlarged view taken generally along the line designated 6-6 in FIG. 4 and which shows the parts before tightening of the contact pin is effected and inwhich FIG. 7 is a view similar to FIG. 6 but which depicts the parts in the positions which they occupy after the contact pin is screwed into its tightened and fully assembled position.

In FIG. 1 the numeral 1 generally designates the elbow housing structure which preferably though not necessarily is constructed of yieldable material. An elongated conductor designated by the numeral 2 enters the housing structure 1 and is surrounded by conventional insulating material 3. A contact pin 4 protrudes outwardly from the lower portion of the elbow housing 1 and, as is well known, is adapted for engaging and making electric contact with the terminal of an electric device such as a power transformer.

For the purpose of interconnecting the elongated conductor 2 with the contact pin 4, a contact sleeve 5 is of hollow construction at its right hand end as indicated at 6 and receives the lefthand end of conductor 2. Contact between these elements is secured and maintained by clamping action as is well known. The contact sleeve 5 is provided at its lefthand end with a shank portion 7 which is inserted within a contact making passage 8 formed within contact body 9 following insertion of contact body 9 into elbow 1 by means of special tool T1 as shown in FIG. 4. Contact making passage 8 is smooth and unthreaded and of larger diameter than shank 7 so as to accommodate relative rotation and transverse lost motion therebetween. The end B of shank 7 is bevelled to facilitate assembly.

Contact pin 4 is provided with threads 10 and with a reduced end portion 11 of smaller diameter than the threaded portion 10 thereof. The contact pin 4 is screwed into the threaded contact making passage 12 formed in contact body 9 until the end 11 of the contact pin 4 engages and forms an indentation in the shank 7 of contact sleeve 5 as indicated at 13 in FIG. 2. Contact pin 4 is provided with an end portion 14 formed of non-conductive material in conventional fashion.

In accordance with the invention, the contact body 9 is disposed in fixed relation within the elbow housing 1 and occupies the position depicted in FIGS. 2 and 4. To facilitate insertion of the contact body 9 into the preformed housing, insertion tool T1 is provided with a handle portion 15 and with a threaded end portion 16 which is adapted to be screwed into the threaded contact making cavity 12 formed in contact body 9. With the contact body securely affixed to the insertion tool T1, the contact body is forced upwardly through the cavity defining passage 17 formed in elbow l to occupy the position shown in FIGS. 2 and 4. Of course the contact making passage 8 is disposed in alignment with the cavity defining passage 18 formed .in the elbow and the contact making threaded passage 12 is automatically disposed in alignment with the cavity defining passage 17 formed in the elbow. With the contact; body mounted within the elbow housing as shown in FIG. 4 the insertion tool 14 is unscrewed and removed. 'The structure is then ready for fieldinstallatiom o Assembly in the field is effected by simply clamping or crimping the contact sleeve 5 onto. the conductor 2 as shown in FIG. 2 and the shank 7 of the contact sleeve 5 is then inserted into the contact making passage 8 simultaneously with the insertion of the contact sleeve and the associated conductor into thev cavity defining passage 18 until the parts occupy the positions depicted in FIG. 2. The transverse dimensions of the exteriorof contact sleeve 5 and the interior of cavity defining passage 18 are such that free relative rotation of these parts is accommodated. Thereafter the contact pin 4 is screwed into the contact making cavity 12 by means of assembly tool T2 as shown in F IG. 5. This tool is provided with a projecting portion 19 which is insertedwithin a transverse passage 20 formed in contact pin 4. Rotation of the handle portion 21 of the tool T2 imparts tightening contact making rotation to contact pin 4 and the contact pin is tightened until a desired contact pressure is established. a

A pull ring 22 is mounted on housing structure 1 and, as is well known, is used in manipulatingthe connector contact pin 4 into and out of contact making relationship with the associated terminal of the adjacent electric apparatus by means of a conventional hot stick or the like. 7

According to a feature of the invention, the exterior surface of the contact body is irregularly configured and acomplementary cavity is formed within the, elbow housing 1 so that movement of the contact body 9 within the elbow housing 1 is prevented. For example, a groove G is formed about the exterior of the contact body 9 and a complementary ridge R is formed in thev interior wall of the housing 1 and is received within the groove G and the exterior of contact body 9 in a plane normal to the axis ofcontact making cavity 16 is polygonal in configuration as shown. in the drawings. Thus relative movement between the contactbody 9v and the housing structure] is automatically prevented so that proper alignment of the contact making passage 8 with the cavity defining passage 18 is automatically assured as well as alignment of the contact making passage 12 with the cavity defining passage 17.

According to one aspect of the invention, substantially constant contact pressure is provided between the end 1 1 of contact pin 4 and the side of shank 7 and between the contact body 9and the contact making threaded portion of contact pin 4 and the smooth unthreaded portion of shank .7. This result is achieved byconstructing the contact making passage 8 of a transverse dimension which is somewhat greater than the exterior transverse dimension of shank 7 as shown in FIG. 6 wherein the parts are shown in untightened condition. The contact making force applied by the contact pin 4 causes the shank 7 to occupy the position depicted in FIG. 7 after contact pressure is established. From FIG. 7, it is apparent that the contact making passage 8 is no longer round but rather is somewhat eliptical indicating that the top portion of. contact making cavity 8 is bowed downwardly somewhat as indicated by the numeral 23 and the sides 24 and 25 of the contact makingpassage 8 are somewhat elongated. The resulting eliptical shape is due to a stretching of the sides 24 and 25, 0f the passage 8 and a slight bending of the upper portion thereof as indicated at 23. Care must be taken to :form the contact body of such material that adequate. contact pressure may be established between the contact surfaces without exceeding the elastic limit of the contact body 9 when the conditions depicted in FIG. 7 are achieved. Under these conditions, the con tact body 9 constitutes a special spring and provides a springlike action whereby substantially constant contact pressure is obtained according to one facet of the invention. When the contact pin is loosened, the parts return to the positions depicted in FIG. 6. In order to deform the passage 8 as described, care mustbe taken to insure that internally threaded passage'l2 formed in the base portion of contact block 9 is sufficiently long to prevent downward distortion of the lower base portion of contact body 9 which portion is of substantial mass. More specifically the threaded length of passage 12 preferably is greater than the transverse dimension of contact pin 4 as is apparent from an inspection of FIGS. 2 and 3. The coupling portion of contact block 9in which contact making'passage 8 is formed is of substantially less mass than the base portion of the contact block and the parts of the coupling portion which define the contact making passage 8"in' a direction normal to the axis thereof are of substantially smaller dimension than the diameter of passage 8.

While the invention is not limited to any particular dimensions of parts or to specific materials, it has been found that the inside diameter of contact making passage 8 may be made 0.375 inches and the outside diameter of shank 7 of contact sleeve 5 may be made 0.370 inches to provide a clearance of 0.005 inch where the normal load current is 200 amperes and where the contact body 9 is constructed of an alloy of aluminum. Furthermore suitable results have been achieved with clearances greater or less than 0.005 inch. A suitable aluminum alloy is commonly known in the trade as 6063-T5.

With the contact pin screwed into its normal tight ened position as shown in FIGS. 2 and 7, the shoulder 26 thereof is spaced from the bottom surface 27 of contact block 9. Thus the entire axial thrust of contact pin 4 in an upward direction is imparted to end'' 11 of the contact pin'thereby insuring high pressure contact between shank 7 of contact sleeve 5 and end 11 of contactpin4. 3

This structure and cooperation of parts is in contrast to the known arrangements described above wherein a thrust shoulder of the contact pin having its friction force disposed'at a greater radius from the axis of the pin absorbs a substantial portion of the contact making thrust force of the contact pin and requires greater turning moment during tightening than is required by this invention. According to this invention, contact pin 4 has no thrust shoulder and the entire friction force of pin 4 is applied at the end thereof insuring high pressure contact and requiring substantially less turning moment because of the small radius of the end of contact pin 4. The improved efficiency achieved by this invention is important since the tools such as T2 are generally capable of applying limited torque only. This feature constitutes a further distinction from known connectors and is fully explained in the manual captioned Design of Machine Elements third edition by M. F.

Spotts pages 202-205 inclusive, published by Prentice- Hall Inc., Englewood Cliffs, N.J., Fifth Printing, 1966.

From the above description it is apparent that according to the invention, a greatly improved connector is provided wherein substantially constant contact pressure is obtained irrespective of ambient or electrical conditions. In addition, a greatly improved method of assembly is provided whereby a conductor such as 2 is interconnected through the connector with a terminal of a piece of electric apparatus without requiring tedious alignment and orienting procedures because the parts are automatically oriented and any chance for error during assembly is completely eliminated according to the invention.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An electric elbow connector comprising a unitary contact body of conducting material having a base portion of substantial mass and a coupling portion of substantially less mass than said base portion, a threaded contact making passage formed in said base portion, a second contact making passage formed in said coupling portion and transversely disposed relative to said threaded contact making passage and in communication therewith, the thickness of the sides and upper portion which define said second contact making passage in a direction normal to the axis of said second passage being of a substantially smaller dimension than the length of the threaded portion of the contact making passage and the length of said second contact making passage axially thereof being substantially less than the length of said threaded contact making passage axially thereof, a contact sleeve having one end of somewhat smaller diameter than the diameter of said second contact making passage and disposed in said second contact making passage, and a contact pin in threaded engagement with said threaded contact making passage and having its inner end in high pressure contact with said one end of said contact sleeve such that said coupling portion is deformed without exceeding the elastic limit thereof but without causing any significant deformation of said base portion of said contact body.

2. A connector according to claim 1 wherein the contact making end of said contact pin is of smaller diameter than the threaded adjacent portion thereof whereby high pressure contact is established between said contact making end of said contact pin and the outer surface of said shank end of said contact sleeve.

3. A connector according to claim 1 wherein the transverse dimension of said contact pin is substantially smaller than the length of said threaded contact making passage.

4. A connector according to claim 1 wherein a preformed housing formed at least in part of yieldable material and having angularly related intersecting cavity defining passages is disposed about said contact body and arranged with each cavity defining passage in coaxial relation with one of said contact making passages in said contact body and wherein the difference in diameter between said one end of said contact sleeve and said second contact making passage is approximately 0.005 inch and wherein said contact body is formed of aluminum alloy. 

1. An electric elbow connector comprising a unitary contact body of conducting material having a base portion of substantial mass and a coupling portion of substantially less mass than said base portion, a threaded contact making passage formed in said base portion, a second contact making passage formed in said coupling portion and transversely disposed relative to said threaded contact making passage and in communication therewith, the thickness of the sides and upper portion which define said second contact making passage in a direction normal to the axis of said second passage being of a substantially smaller dimension than the length of the threaded portion of the contact making passage and the length of said second contact making passage axially thereof being substantially less than the length of said threaded contact making passage axially thereof, a contact sleeve having one end of somewhat smaller diameter than the diameter of said second contact making passage and disposed in said second contact making passage, and a contact pin in threaded engagement with said threaded contact making passage and having its inner end in high pressure contact with said one end of said contact sleeve such that said coupling portion is deformed without exceeding the elastic limit thereof but without causing any significant deformation of said base portion of said contact body.
 2. A connector according to claim 1 wherein the contact making end of said contact pin is of smaller diameter than the threaded adjacent portion thereof whereby high pressure contact is established between said contact making end of said contact pin and the outer surface of said shank end of said contact sleeve.
 3. A connector according to claim 1 wherein the transverse dimension of said contact pin is substantially smaller than the length of said threaded contact making passage.
 4. A connector according to claim 1 wherein a preformed housing formed at least in part of yieldable material and having angularly related intersecting cavity defining passages is disposed about said contact body and arranged with each cavity defining passage in coaxial relation with one of said contact making passages in said contact body and wherein the difference in diameter between said one end of said contact sleeve and said second contact making passage is approximately 0.005 inch and wherein said contact body is formed of aluminum alloy. 